±320 kV直流电缆终端界面气隙缺陷的直流局放试验电压确定方法  

Determination method of DC partial discharge test voltage for air gap defects at interface of ±320 kV DC cable termination

作　　者：赵洋 魏思芸 马宪伟 程养春[2] 夏荣 ZHAO Yang;WEI Siyun;MA Xianwei;CHENG Yangchun;XIA Rong(State Grid Beijing Cable Company,Beijing 100027,China;Beijing Key Laboratory of High Voltage and EMC,North China Electric Power University,Beijing 102206,China;China Electric Power Research Institute,Beijing 100092,China)

机构地区：[1]国网北京电力公司电缆分公司,北京100027 [2]华北电力大学高电压与电磁兼容北京市重点实验室,北京102206 [3]中国电力科学研究院有限公司,北京100092

出　　处：《绝缘材料》2023年第3期61-69,共9页Insulating Materials

基　　金：国家电网有限公司总部科技项目(5500-202111118A-0-0-00)。

摘　　要：局部放电试验作为交流系统中缺陷检测的有效手段得到了广泛使用,但是直流电缆的直流局放检测试验方法还处于初级阶段。为了确定直流局部放电检测的现场试验电压,本文研究了直流试验电压幅值与±320 kV电缆预制式终端气隙缺陷检出率之间的关系。将±320 kV电缆预制式终端复合界面上的气隙缺陷作为研究对象,通过多物理场仿真计算气隙缺陷内的最大电场强度,以电场强度超过阈值来判断该缺陷是否可能发生局部放电;基于概率统计分析,建立了考虑电缆运行温度和气隙位置等随机因素条件下电缆接头的局部放电概率密度函数,给出了缺陷检出率与环境温度和直流试验电压的函数关系式。结果表明:电缆界面的气隙缺陷检出率与环境温度和直流局放试验电压的函数关系式符合4次方幂函数关系式,且检出率水平随环境温度的升高而升高;若直流试验电压取1.85U0,20℃时的检出率为99.25%,30℃时的检出率可达99.85%。据此函数关系式可以确定直流试验电压幅值。Partial discharge test has been widely used as an effective means of defect detection in AC system, but the partial discharge detection test method of DC cable is still in its infancy. In order to determine the field test voltage of DC partial discharge detection, the relationship between DC test voltage amplitude and air gap defect detection rate of ±320 kV cable prefabricated terminal was studied in this paper. Taking the air gap defect commonly existing on the composite interface of ±320 kV cable prefabricated terminal as the research object, we calculated the maximum electric field intensity in the air gap through multi physical field simulation, and whether the defect may produce partial discharge was judged by the electric field intensity exceeding the threshold. Based on the probability and statistical analysis, the partial discharge probability density function of cable joints under the condition of considering random factors such as cable operating temperature and air gap position was established, and the function equation between defect detection rate and ambient temperature and DC test voltage was presented. The results show that the function equation between the detection rate of air gap defect at the cable interface and the ambient temperature and DC partial discharge test voltage conforms to the fourth power function, and the detection rate increases with the increase of ambient temperature. If the DC test voltage is 1.85U0, the detection rate is 99.25% at 20℃, and the detection rate can reach 99.85% at 30℃. The DC test voltag amplitude can be determined by the function equation.

关 键 词：直流电缆 电缆终端 气隙缺陷 局部放电 试验电压 检出率 

分 类 号：TM835[电气工程—高电压与绝缘技术]